its rather simple to do
to activate the timer simply click on the Plus icon in your contact list or in a conversation, open the Count Down menu, and select Enable CountDown
this will give you a toast saying "Counter is now enabled"
should that not happen, the counter may already be active, you can check by typing "!cdenable" (without the quotes) in any conversation window.
once the Counter is active, all you have to do is open the congif window, and set the time and date you want the the timer to end, and also you can have the script remove any values that are 0 (zero) I.E.: "0 Days 3 Hours" will display as only "3 Hours"
if you have any problems you can reply and i'll try to get back to you